[C++11] Use 'nullptr'. Lex edition.

llvm-svn: 209083

17 files changed, 239 insertions, 227 deletions

diff --git a/clang/lib/Lex/HeaderMap.cpp b/clang/lib/Lex/HeaderMap.cpp
index 2d07428ea6fa..f6c658e11926 100644
--- a/clang/lib/Lex/HeaderMap.cpp
+++ b/clang/lib/Lex/HeaderMap.cpp
@@ -79,10 +79,10 @@ static inline unsigned HashHMapKey(StringRef Str) {
 const HeaderMap *HeaderMap::Create(const FileEntry *FE, FileManager &FM) {
   // If the file is too small to be a header map, ignore it.
   unsigned FileSize = FE->getSize();
-  if (FileSize <= sizeof(HMapHeader)) return 0;
+  if (FileSize <= sizeof(HMapHeader)) return nullptr;
 
   std::unique_ptr<const llvm::MemoryBuffer> FileBuffer(FM.getBufferForFile(FE));
-  if (!FileBuffer) return 0;  // Unreadable file?
+  if (!FileBuffer) return nullptr;  // Unreadable file?
   const char *FileStart = FileBuffer->getBufferStart();
 
   // We know the file is at least as big as the header, check it now.
@@ -98,9 +98,9 @@ const HeaderMap *HeaderMap::Create(const FileEntry *FE, FileManager &FM) {
            Header->Version == llvm::ByteSwap_16(HMAP_HeaderVersion))
     NeedsByteSwap = true;  // Mixed endianness headermap.
   else
-    return 0;  // Not a header map.
+    return nullptr;  // Not a header map.
 
-  if (Header->Reserved != 0) return 0;
+  if (Header->Reserved != 0) return nullptr;
 
   // Okay, everything looks good, create the header map.
   return new HeaderMap(FileBuffer.release(), NeedsByteSwap);
@@ -165,7 +165,7 @@ const char *HeaderMap::getString(unsigned StrTabIdx) const {
 
   // Check for invalid index.
   if (StrTabIdx >= FileBuffer->getBufferSize())
-    return 0;
+    return nullptr;
 
   // Otherwise, we have a valid pointer into the file.  Just return it.  We know
   // that the "string" can not overrun the end of the file, because the buffer
@@ -205,7 +205,7 @@ const FileEntry *HeaderMap::LookupFile(
   SmallString<1024> Path;
   StringRef Dest = lookupFilename(Filename, Path);
   if (Dest.empty())
-    return 0;
+    return nullptr;
 
   return FM.getFile(Dest);
 }
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 6d68c38a2c1f..a1dbe4943451 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -37,7 +37,7 @@ HeaderFileInfo::getControllingMacro(ExternalIdentifierLookup *External) {
     return ControllingMacro;
 
   if (!ControllingMacroID || !External)
-    return 0;
+    return nullptr;
 
   ControllingMacro = External->GetIdentifier(ControllingMacroID);
   return ControllingMacro;
@@ -55,8 +55,8 @@ HeaderSearch::HeaderSearch(IntrusiveRefCntPtr<HeaderSearchOptions> HSOpts,
   SystemDirIdx = 0;
   NoCurDirSearch = false;
 
-  ExternalLookup = 0;
-  ExternalSource = 0;
+  ExternalLookup = nullptr;
+  ExternalSource = nullptr;
   NumIncluded = 0;
   NumMultiIncludeFileOptzn = 0;
   NumFrameworkLookups = NumSubFrameworkLookups = 0;
@@ -110,7 +110,7 @@ const HeaderMap *HeaderSearch::CreateHeaderMap(const FileEntry *FE) {
     return HM;
   }
 
-  return 0;
+  return nullptr;
 }
 
 std::string HeaderSearch::getModuleFileName(Module *Module) {
@@ -277,12 +277,12 @@ const FileEntry *DirectoryLookup::LookupFile(
     // Concatenate the requested file onto the directory.
     TmpDir = getDir()->getName();
     llvm::sys::path::append(TmpDir, Filename);
-    if (SearchPath != NULL) {
+    if (SearchPath) {
       StringRef SearchPathRef(getDir()->getName());
       SearchPath->clear();
       SearchPath->append(SearchPathRef.begin(), SearchPathRef.end());
     }
-    if (RelativePath != NULL) {
+    if (RelativePath) {
       RelativePath->clear();
       RelativePath->append(Filename.begin(), Filename.end());
     }
@@ -301,7 +301,7 @@ const FileEntry *DirectoryLookup::LookupFile(
   SmallString<1024> Path;
   StringRef Dest = HM->lookupFilename(Filename, Path);
   if (Dest.empty())
-    return 0;
+    return nullptr;
 
   const FileEntry *Result;
 
@@ -320,12 +320,12 @@ const FileEntry *DirectoryLookup::LookupFile(
   }
 
   if (Result) {
-    if (SearchPath != NULL) {
+    if (SearchPath) {
       StringRef SearchPathRef(getName());
       SearchPath->clear();
       SearchPath->append(SearchPathRef.begin(), SearchPathRef.end());
     }
-    if (RelativePath != NULL) {
+    if (RelativePath) {
       RelativePath->clear();
       RelativePath->append(Filename.begin(), Filename.end());
     }
@@ -397,7 +397,7 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
 
   // Framework names must have a '/' in the filename.
   size_t SlashPos = Filename.find('/');
-  if (SlashPos == StringRef::npos) return 0;
+  if (SlashPos == StringRef::npos) return nullptr;
 
   // Find out if this is the home for the specified framework, by checking
   // HeaderSearch.  Possible answers are yes/no and unknown.
@@ -406,7 +406,7 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
 
   // If it is known and in some other directory, fail.
   if (CacheEntry.Directory && CacheEntry.Directory != getFrameworkDir())
-    return 0;
+    return nullptr;
 
   // Otherwise, construct the path to this framework dir.
 
@@ -424,12 +424,12 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
   FrameworkName += ".framework/";
 
   // If the cache entry was unresolved, populate it now.
-  if (CacheEntry.Directory == 0) {
+  if (!CacheEntry.Directory) {
     HS.IncrementFrameworkLookupCount();
 
     // If the framework dir doesn't exist, we fail.
     const DirectoryEntry *Dir = FileMgr.getDirectory(FrameworkName.str());
-    if (Dir == 0) return 0;
+    if (!Dir) return nullptr;
 
     // Otherwise, if it does, remember that this is the right direntry for this
     // framework.
@@ -449,7 +449,7 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
   // Set the 'user-specified system framework' flag.
   InUserSpecifiedSystemFramework = CacheEntry.IsUserSpecifiedSystemFramework;
 
-  if (RelativePath != NULL) {
+  if (RelativePath) {
     RelativePath->clear();
     RelativePath->append(Filename.begin()+SlashPos+1, Filename.end());
   }
@@ -459,7 +459,7 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
 
   FrameworkName += "Headers/";
 
-  if (SearchPath != NULL) {
+  if (SearchPath) {
     SearchPath->clear();
     // Without trailing '/'.
     SearchPath->append(FrameworkName.begin(), FrameworkName.end()-1);
@@ -473,7 +473,7 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
     const char *Private = "Private";
     FrameworkName.insert(FrameworkName.begin()+OrigSize, Private,
                          Private+strlen(Private));
-    if (SearchPath != NULL)
+    if (SearchPath)
       SearchPath->insert(SearchPath->begin()+OrigSize, Private,
                          Private+strlen(Private));
 
@@ -590,14 +590,14 @@ const FileEntry *HeaderSearch::LookupFile(
     
   // If 'Filename' is absolute, check to see if it exists and no searching.
   if (llvm::sys::path::is_absolute(Filename)) {
-    CurDir = 0;
+    CurDir = nullptr;
 
     // If this was an #include_next "/absolute/file", fail.
-    if (FromDir) return 0;
+    if (FromDir) return nullptr;
 
-    if (SearchPath != NULL)
+    if (SearchPath)
       SearchPath->clear();
-    if (RelativePath != NULL) {
+    if (RelativePath) {
       RelativePath->clear();
       RelativePath->append(Filename.begin(), Filename.end());
     }
@@ -606,7 +606,7 @@ const FileEntry *HeaderSearch::LookupFile(
   }
 
   // This is the header that MSVC's header search would have found.
-  const FileEntry *MSFE = 0;
+  const FileEntry *MSFE = nullptr;
   ModuleMap::KnownHeader MSSuggestedModule;
 
   // Unless disabled, check to see if the file is in the #includer's
@@ -651,12 +651,12 @@ const FileEntry *HeaderSearch::LookupFile(
         ToHFI.IndexHeaderMapHeader = IndexHeaderMapHeader;
         ToHFI.Framework = Framework;
 
-        if (SearchPath != NULL) {
+        if (SearchPath) {
           StringRef SearchPathRef(Includer->getDir()->getName());
           SearchPath->clear();
           SearchPath->append(SearchPathRef.begin(), SearchPathRef.end());
         }
-        if (RelativePath != NULL) {
+        if (RelativePath) {
           RelativePath->clear();
           RelativePath->append(Filename.begin(), Filename.end());
         }
@@ -682,7 +682,7 @@ const FileEntry *HeaderSearch::LookupFile(
     }
   }
 
-  CurDir = 0;
+  CurDir = nullptr;
 
   // If this is a system #include, ignore the user #include locs.
   unsigned i = isAngled ? AngledDirIdx : 0;
@@ -806,7 +806,7 @@ const FileEntry *HeaderSearch::LookupFile(
     }
   }
 
-  if (checkMSVCHeaderSearch(Diags, MSFE, 0, IncludeLoc)) {
+  if (checkMSVCHeaderSearch(Diags, MSFE, nullptr, IncludeLoc)) {
     if (SuggestedModule)
       *SuggestedModule = MSSuggestedModule;
     return MSFE;
@@ -814,7 +814,7 @@ const FileEntry *HeaderSearch::LookupFile(
 
   // Otherwise, didn't find it. Remember we didn't find this.
   CacheLookup.HitIdx = SearchDirs.size();
-  return 0;
+  return nullptr;
 }
 
 /// LookupSubframeworkHeader - Look up a subframework for the specified
@@ -833,7 +833,7 @@ LookupSubframeworkHeader(StringRef Filename,
   // Framework names must have a '/' in the filename.  Find it.
   // FIXME: Should we permit '\' on Windows?
   size_t SlashPos = Filename.find('/');
-  if (SlashPos == StringRef::npos) return 0;
+  if (SlashPos == StringRef::npos) return nullptr;
 
   // Look up the base framework name of the ContextFileEnt.
   const char *ContextName = ContextFileEnt->getName();
@@ -841,10 +841,10 @@ LookupSubframeworkHeader(StringRef Filename,
   // If the context info wasn't a framework, couldn't be a subframework.
   const unsigned DotFrameworkLen = 10;
   const char *FrameworkPos = strstr(ContextName, ".framework");
-  if (FrameworkPos == 0 || 
+  if (FrameworkPos == nullptr ||
       (FrameworkPos[DotFrameworkLen] != '/' && 
        FrameworkPos[DotFrameworkLen] != '\\'))
-    return 0;
+    return nullptr;
 
   SmallString<1024> FrameworkName(ContextName, FrameworkPos+DotFrameworkLen+1);
 
@@ -861,24 +861,24 @@ LookupSubframeworkHeader(StringRef Filename,
       CacheLookup.getKeyLength() == FrameworkName.size() &&
       memcmp(CacheLookup.getKeyData(), &FrameworkName[0],
              CacheLookup.getKeyLength()) != 0)
-    return 0;
+    return nullptr;
 
   // Cache subframework.
-  if (CacheLookup.getValue().Directory == 0) {
+  if (!CacheLookup.getValue().Directory) {
     ++NumSubFrameworkLookups;
 
     // If the framework dir doesn't exist, we fail.
     const DirectoryEntry *Dir = FileMgr.getDirectory(FrameworkName.str());
-    if (Dir == 0) return 0;
+    if (!Dir) return nullptr;
 
     // Otherwise, if it does, remember that this is the right direntry for this
     // framework.
     CacheLookup.getValue().Directory = Dir;
   }
 
-  const FileEntry *FE = 0;
+  const FileEntry *FE = nullptr;
 
-  if (RelativePath != NULL) {
+  if (RelativePath) {
     RelativePath->clear();
     RelativePath->append(Filename.begin()+SlashPos+1, Filename.end());
   }
@@ -886,7 +886,7 @@ LookupSubframeworkHeader(StringRef Filename,
   // Check ".../Frameworks/HIToolbox.framework/Headers/HIToolbox.h"
   SmallString<1024> HeadersFilename(FrameworkName);
   HeadersFilename += "Headers/";
-  if (SearchPath != NULL) {
+  if (SearchPath) {
     SearchPath->clear();
     // Without trailing '/'.
     SearchPath->append(HeadersFilename.begin(), HeadersFilename.end()-1);
@@ -898,7 +898,7 @@ LookupSubframeworkHeader(StringRef Filename,
     // Check ".../Frameworks/HIToolbox.framework/PrivateHeaders/HIToolbox.h"
     HeadersFilename = FrameworkName;
     HeadersFilename += "PrivateHeaders/";
-    if (SearchPath != NULL) {
+    if (SearchPath) {
       SearchPath->clear();
       // Without trailing '/'.
       SearchPath->append(HeadersFilename.begin(), HeadersFilename.end()-1);
@@ -906,7 +906,7 @@ LookupSubframeworkHeader(StringRef Filename,
 
     HeadersFilename.append(Filename.begin()+SlashPos+1, Filename.end());
     if (!(FE = FileMgr.getFile(HeadersFilename.str(), /*openFile=*/true)))
-      return 0;
+      return nullptr;
   }
 
   // This file is a system header or C++ unfriendly if the old file is.
@@ -1228,15 +1228,15 @@ Module *HeaderSearch::loadFrameworkModule(StringRef Name,
     
   case LMM_AlreadyLoaded:
   case LMM_NoDirectory:
-    return 0;
-    
+    return nullptr;
+
   case LMM_NewlyLoaded:
     return ModMap.findModule(Name);
   }
 
 
   // Try to infer a module map from the framework directory.
-  return ModMap.inferFrameworkModule(Name, Dir, IsSystem, /*Parent=*/0);
+  return ModMap.inferFrameworkModule(Name, Dir, IsSystem, /*Parent=*/nullptr);
 }
 
 
diff --git a/clang/lib/Lex/Lexer.cpp b/clang/lib/Lex/Lexer.cpp
index 2e859d663ffc..ff96cd99d33a 100644
--- a/clang/lib/Lex/Lexer.cpp
+++ b/clang/lib/Lex/Lexer.cpp
@@ -379,7 +379,7 @@ unsigned Lexer::getSpelling(const Token &Tok, const char *&Buffer,
                             const LangOptions &LangOpts, bool *Invalid) {
   assert((int)Tok.getLength() >= 0 && "Token character range is bogus!");
 
-  const char *TokStart = 0;
+  const char *TokStart = nullptr;
   // NOTE: this has to be checked *before* testing for an IdentifierInfo.
   if (Tok.is(tok::raw_identifier))
     TokStart = Tok.getRawIdentifier().data();
@@ -395,7 +395,7 @@ unsigned Lexer::getSpelling(const Token &Tok, const char *&Buffer,
   if (Tok.isLiteral())
     TokStart = Tok.getLiteralData();
 
-  if (TokStart == 0) {
+  if (!TokStart) {
     // Compute the start of the token in the input lexer buffer.
     bool CharDataInvalid = false;
     TokStart = SourceMgr.getCharacterData(Tok.getLocation(), &CharDataInvalid);
@@ -1286,7 +1286,7 @@ Slash:
   if (Ptr[0] == '?' && Ptr[1] == '?') {
     // If this is actually a legal trigraph (not something like "??x"), emit
     // a trigraph warning.  If so, and if trigraphs are enabled, return it.
-    if (char C = DecodeTrigraphChar(Ptr+2, Tok ? this : 0)) {
+    if (char C = DecodeTrigraphChar(Ptr+2, Tok ? this : nullptr)) {
       // Remember that this token needs to be cleaned.
       if (Tok) Tok->setFlag(Token::NeedsCleaning);
 
@@ -1449,7 +1449,7 @@ static void maybeDiagnoseIDCharCompat(DiagnosticsEngine &Diags, uint32_t C,
 bool Lexer::tryConsumeIdentifierUCN(const char *&CurPtr, unsigned Size,
                                     Token &Result) {
   const char *UCNPtr = CurPtr + Size;
-  uint32_t CodePoint = tryReadUCN(UCNPtr, CurPtr, /*Token=*/0);
+  uint32_t CodePoint = tryReadUCN(UCNPtr, CurPtr, /*Token=*/nullptr);
   if (CodePoint == 0 || !isAllowedIDChar(CodePoint, LangOpts))
     return false;
 
@@ -1732,7 +1732,8 @@ const char *Lexer::LexUDSuffix(Token &Result, const char *CurPtr,
 /// either " or L" or u8" or u" or U".
 bool Lexer::LexStringLiteral(Token &Result, const char *CurPtr,
                              tok::TokenKind Kind) {
-  const char *NulCharacter = 0; // Does this string contain the \0 character?
+  // Does this string contain the \0 character?
+  const char *NulCharacter = nullptr;
 
   if (!isLexingRawMode() &&
       (Kind == tok::utf8_string_literal ||
@@ -1868,7 +1869,8 @@ bool Lexer::LexRawStringLiteral(Token &Result, const char *CurPtr,
 /// LexAngledStringLiteral - Lex the remainder of an angled string literal,
 /// after having lexed the '<' character.  This is used for #include filenames.
 bool Lexer::LexAngledStringLiteral(Token &Result, const char *CurPtr) {
-  const char *NulCharacter = 0; // Does this string contain the \0 character?
+  // Does this string contain the \0 character?
+  const char *NulCharacter = nullptr;
   const char *AfterLessPos = CurPtr;
   char C = getAndAdvanceChar(CurPtr, Result);
   while (C != '>') {
@@ -1905,7 +1907,8 @@ bool Lexer::LexAngledStringLiteral(Token &Result, const char *CurPtr) {
 /// lexed either ' or L' or u' or U'.
 bool Lexer::LexCharConstant(Token &Result, const char *CurPtr,
                             tok::TokenKind Kind) {
-  const char *NulCharacter = 0; // Does this character contain the \0 character?
+  // Does this character contain the \0 character?
+  const char *NulCharacter = nullptr;
 
   if (!isLexingRawMode() &&
       (Kind == tok::utf16_char_constant || Kind == tok::utf32_char_constant))
@@ -2606,7 +2609,7 @@ static const char *FindConflictEnd(const char *CurPtr, const char *BufferEnd,
     }
     return RestOfBuffer.data()+Pos;
   }
-  return 0;
+  return nullptr;
 }
 
 /// IsStartOfConflictMarker - If the specified pointer is the start of a version
@@ -2916,7 +2919,7 @@ bool Lexer::LexTokenInternal(Token &Result, bool TokAtPhysicalStartOfLine) {
 LexNextToken:
   // New token, can't need cleaning yet.
   Result.clearFlag(Token::NeedsCleaning);
-  Result.setIdentifierInfo(0);
+  Result.setIdentifierInfo(nullptr);
 
   // CurPtr - Cache BufferPtr in an automatic variable.
   const char *CurPtr = BufferPtr;
diff --git a/clang/lib/Lex/LiteralSupport.cpp b/clang/lib/Lex/LiteralSupport.cpp
index 80e025def7b3..810d7c28b205 100644
--- a/clang/lib/Lex/LiteralSupport.cpp
+++ b/clang/lib/Lex/LiteralSupport.cpp
@@ -195,7 +195,7 @@ static unsigned ProcessCharEscape(const char *ThisTokBegin,
         << std::string(1, ResultChar);
     break;
   default:
-    if (Diags == 0)
+    if (!Diags)
       break;
 
     if (isPrintable(ResultChar))
@@ -340,7 +340,7 @@ static int MeasureUCNEscape(const char *ThisTokBegin, const char *&ThisTokBuf,
   FullSourceLoc Loc;
 
   if (!ProcessUCNEscape(ThisTokBegin, ThisTokBuf, ThisTokEnd, UcnVal,
-                        UcnLen, Loc, 0, Features, true)) {
+                        UcnLen, Loc, nullptr, Features, true)) {
     HadError = true;
     return 0;
   }
@@ -571,7 +571,7 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
   // Parse the suffix.  At this point we can classify whether we have an FP or
   // integer constant.
   bool isFPConstant = isFloatingLiteral();
-  const char *ImaginarySuffixLoc = 0;
+  const char *ImaginarySuffixLoc = nullptr;
 
   // Loop over all of the characters of the suffix.  If we see something bad,
   // we break out of the loop.
@@ -1254,7 +1254,7 @@ StringLiteralParser::
 StringLiteralParser(const Token *StringToks, unsigned NumStringToks,
                     Preprocessor &PP, bool Complain)
   : SM(PP.getSourceManager()), Features(PP.getLangOpts()),
-    Target(PP.getTargetInfo()), Diags(Complain ? &PP.getDiagnostics() : 0),
+    Target(PP.getTargetInfo()), Diags(Complain ? &PP.getDiagnostics() :nullptr),
     MaxTokenLength(0), SizeBound(0), CharByteWidth(0), Kind(tok::unknown),
     ResultPtr(ResultBuf.data()), hadError(false), Pascal(false) {
   init(StringToks, NumStringToks);
diff --git a/clang/lib/Lex/MacroArgs.cpp b/clang/lib/Lex/MacroArgs.cpp
index 82c627a1f941..a746fb7f48bf 100644
--- a/clang/lib/Lex/MacroArgs.cpp
+++ b/clang/lib/Lex/MacroArgs.cpp
@@ -27,7 +27,7 @@ MacroArgs *MacroArgs::create(const MacroInfo *MI,
                              bool VarargsElided, Preprocessor &PP) {
   assert(MI->isFunctionLike() &&
          "Can't have args for an object-like macro!");
-  MacroArgs **ResultEnt = 0;
+  MacroArgs **ResultEnt = nullptr;
   unsigned ClosestMatch = ~0U;
   
   // See if we have an entry with a big enough argument list to reuse on the
@@ -46,7 +46,7 @@ MacroArgs *MacroArgs::create(const MacroInfo *MI,
     }
   
   MacroArgs *Result;
-  if (ResultEnt == 0) {
+  if (!ResultEnt) {
     // Allocate memory for a MacroArgs object with the lexer tokens at the end.
     Result = (MacroArgs*)malloc(sizeof(MacroArgs) + 
                                 UnexpArgTokens.size() * sizeof(Token));
diff --git a/clang/lib/Lex/MacroInfo.cpp b/clang/lib/Lex/MacroInfo.cpp
index 8547ad3f72fc..cb3945652fd1 100644
--- a/clang/lib/Lex/MacroInfo.cpp
+++ b/clang/lib/Lex/MacroInfo.cpp
@@ -17,7 +17,7 @@ using namespace clang;
 
 MacroInfo::MacroInfo(SourceLocation DefLoc)
   : Location(DefLoc),
-    ArgumentList(0),
+    ArgumentList(nullptr),
     NumArguments(0),
     IsDefinitionLengthCached(false),
     IsFunctionLike(false),
@@ -145,7 +145,8 @@ MacroDirective::DefInfo MacroDirective::getDefinition() {
       isPublic = VisMD->isPublic();
   }
 
-  return DefInfo(0, UndefLoc, !isPublic.hasValue() || isPublic.getValue());
+  return DefInfo(nullptr, UndefLoc,
+                 !isPublic.hasValue() || isPublic.getValue());
 }
 
 const MacroDirective::DefInfo
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index bdf71b5f4a16..0538d33670cf 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -42,7 +42,7 @@ ModuleMap::resolveExport(Module *Mod,
   // We may have just a wildcard.
   if (Unresolved.Id.empty()) {
     assert(Unresolved.Wildcard && "Invalid unresolved export");
-    return Module::ExportDecl(0, true);
+    return Module::ExportDecl(nullptr, true);
   }
   
   // Resolve the module-id.
@@ -62,7 +62,7 @@ Module *ModuleMap::resolveModuleId(const ModuleId &Id, Module *Mod,
       Diags.Report(Id[0].second, diag::err_mmap_missing_module_unqualified)
       << Id[0].first << Mod->getFullModuleName();
 
-    return 0;
+    return nullptr;
   }
 
   // Dig into the module path.
@@ -74,7 +74,7 @@ Module *ModuleMap::resolveModuleId(const ModuleId &Id, Module *Mod,
         << Id[I].first << Context->getFullModuleName()
         << SourceRange(Id[0].second, Id[I-1].second);
 
-      return 0;
+      return nullptr;
     }
 
     Context = Sub;
@@ -87,8 +87,8 @@ ModuleMap::ModuleMap(SourceManager &SourceMgr, DiagnosticsEngine &Diags,
                      const LangOptions &LangOpts, const TargetInfo *Target,
                      HeaderSearch &HeaderInfo)
     : SourceMgr(SourceMgr), Diags(Diags), LangOpts(LangOpts), Target(Target),
-      HeaderInfo(HeaderInfo), BuiltinIncludeDir(0), CompilingModule(0),
-      SourceModule(0) {}
+      HeaderInfo(HeaderInfo), BuiltinIncludeDir(nullptr),
+      CompilingModule(nullptr), SourceModule(nullptr) {}
 
 ModuleMap::~ModuleMap() {
   for (llvm::StringMap<Module *>::iterator I = Modules.begin(), 
@@ -247,8 +247,8 @@ void ModuleMap::diagnoseHeaderInclusion(Module *RequestingModule,
     resolveUses(RequestingModule, /*Complain=*/false);
 
   bool Excluded = false;
-  Module *Private = NULL;
-  Module *NotUsed = NULL;
+  Module *Private = nullptr;
+  Module *NotUsed = nullptr;
 
   HeadersMap::iterator Known = findKnownHeader(File);
   if (Known != Headers.end()) {
@@ -284,14 +284,14 @@ void ModuleMap::diagnoseHeaderInclusion(Module *RequestingModule,
   }
 
   // We have found a header, but it is private.
-  if (Private != NULL) {
+  if (Private) {
     Diags.Report(FilenameLoc, diag::error_use_of_private_header_outside_module)
         << Filename;
     return;
   }
 
   // We have found a module, but we don't use it.
-  if (NotUsed != NULL) {
+  if (NotUsed) {
     Diags.Report(FilenameLoc, diag::error_undeclared_use_of_module)
         << RequestingModule->getFullModuleName() << Filename;
     return;
@@ -387,7 +387,7 @@ ModuleMap::findModuleForHeader(const FileEntry *File,
         // If inferred submodules export everything they import, add a
         // wildcard to the set of exports.
         if (UmbrellaModule->InferExportWildcard && Result->Exports.empty())
-          Result->Exports.push_back(Module::ExportDecl(0, true));
+          Result->Exports.push_back(Module::ExportDecl(nullptr, true));
       }
 
       // Infer a submodule with the same name as this header file.
@@ -402,7 +402,7 @@ ModuleMap::findModuleForHeader(const FileEntry *File,
       // If inferred submodules export everything they import, add a
       // wildcard to the set of exports.
       if (UmbrellaModule->InferExportWildcard && Result->Exports.empty())
-        Result->Exports.push_back(Module::ExportDecl(0, true));
+        Result->Exports.push_back(Module::ExportDecl(nullptr, true));
     } else {
       // Record each of the directories we stepped through as being part of
       // the module we found, since the umbrella header covers them all.
@@ -424,7 +424,7 @@ ModuleMap::findModuleForHeader(const FileEntry *File,
 }
 
 bool ModuleMap::isHeaderInUnavailableModule(const FileEntry *Header) const {
-  return isHeaderUnavailableInModule(Header, 0);
+  return isHeaderUnavailableInModule(Header, nullptr);
 }
 
 bool
@@ -513,8 +513,8 @@ Module *ModuleMap::findModule(StringRef Name) const {
   llvm::StringMap<Module *>::const_iterator Known = Modules.find(Name);
   if (Known != Modules.end())
     return Known->getValue();
-  
-  return 0;
+
+  return nullptr;
 }
 
 Module *ModuleMap::lookupModuleUnqualified(StringRef Name,
@@ -665,7 +665,7 @@ ModuleMap::inferFrameworkModule(StringRef ModuleName,
 
     // If we're not allowed to infer a framework module, don't.
     if (!canInfer)
-      return 0;
+      return nullptr;
   } else
     ModuleMapFile = Parent->ModuleMap;
 
@@ -679,8 +679,8 @@ ModuleMap::inferFrameworkModule(StringRef ModuleName,
   // framework to load *everything*. But, it's not clear that this is a good
   // idea.
   if (!UmbrellaHeader)
-    return 0;
-  
+    return nullptr;
+
   Module *Result = new Module(ModuleName, SourceLocation(), Parent, ModuleMapFile,
                               /*IsFramework=*/true, /*IsExplicit=*/false);
   if (LangOpts.CurrentModule == ModuleName) {
@@ -699,8 +699,8 @@ ModuleMap::inferFrameworkModule(StringRef ModuleName,
   UmbrellaDirs[UmbrellaHeader->getDir()] = Result;
   
   // export *
-  Result->Exports.push_back(Module::ExportDecl(0, true));
-  
+  Result->Exports.push_back(Module::ExportDecl(nullptr, true));
+
   // module * { export * }
   Result->InferSubmodules = true;
   Result->InferExportWildcard = true;
@@ -787,7 +787,7 @@ void ModuleMap::addHeader(Module *Mod, const FileEntry *Header,
 const FileEntry *
 ModuleMap::getContainingModuleMapFile(Module *Module) const {
   if (Module->DefinitionLoc.isInvalid())
-    return 0;
+    return nullptr;
 
   return SourceMgr.getFileEntryForID(
            SourceMgr.getFileID(Module->DefinitionLoc));
@@ -864,14 +864,13 @@ bool ModuleMap::resolveConflicts(Module *Mod, bool Complain) {
 
 Module *ModuleMap::inferModuleFromLocation(FullSourceLoc Loc) {
   if (Loc.isInvalid())
-    return 0;
-  
+    return nullptr;
+
   // Use the expansion location to determine which module we're in.
   FullSourceLoc ExpansionLoc = Loc.getExpansionLoc();
   if (!ExpansionLoc.isFileID())
-    return 0;  
-  
-  
+    return nullptr;
+
   const SourceManager &SrcMgr = Loc.getManager();
   FileID ExpansionFileID = ExpansionLoc.getFileID();
   
@@ -885,12 +884,12 @@ Module *ModuleMap::inferModuleFromLocation(FullSourceLoc Loc) {
     // any included header has an associated module.
     SourceLocation IncludeLoc = SrcMgr.getIncludeLoc(ExpansionFileID);
     if (IncludeLoc.isInvalid())
-      return 0;
-    
+      return nullptr;
+
     ExpansionFileID = SrcMgr.getFileID(IncludeLoc);
   }
-  
-  return 0;
+
+  return nullptr;
 }
 
 //----------------------------------------------------------------------------//
@@ -936,7 +935,7 @@ namespace clang {
       Kind = EndOfFile;
       Location = 0;
       StringLength = 0;
-      StringData = 0;
+      StringData = nullptr;
     }
     
     bool is(TokenKind K) const { return Kind == K; }
@@ -1036,7 +1035,7 @@ namespace clang {
       : L(L), SourceMgr(SourceMgr), Target(Target), Diags(Diags), Map(Map), 
         ModuleMapFile(ModuleMapFile), Directory(Directory),
         BuiltinIncludeDir(BuiltinIncludeDir), IsSystem(IsSystem),
-        HadError(false), ActiveModule(0)
+        HadError(false), ActiveModule(nullptr)
     {
       Tok.clear();
       consumeToken();
@@ -1322,7 +1321,7 @@ void ModuleMapParser::parseModuleDecl() {
   if (Id.size() > 1) {
     // This module map defines a submodule. Go find the module of which it
     // is a submodule.
-    ActiveModule = 0;
+    ActiveModule = nullptr;
     for (unsigned I = 0, N = Id.size() - 1; I != N; ++I) {
       if (Module *Next = Map.lookupModuleQualified(Id[I].first, ActiveModule)) {
         ActiveModule = Next;
@@ -1648,8 +1647,8 @@ void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind LeadingToken,
   }
 
   // Look for this file.
-  const FileEntry *File = 0;
-  const FileEntry *BuiltinFile = 0;
+  const FileEntry *File = nullptr;
+  const FileEntry *BuiltinFile = nullptr;
   SmallString<128> PathName;
   if (llvm::sys::path::is_absolute(Header.FileName)) {
     PathName = Header.FileName;
@@ -1692,7 +1691,7 @@ void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind LeadingToken,
         // up adding both (later).
         if (!File && BuiltinFile) {
           File = BuiltinFile;
-          BuiltinFile = 0;
+          BuiltinFile = nullptr;
         }
       }
     }
@@ -1763,7 +1762,7 @@ void ModuleMapParser::parseUmbrellaDirDecl(SourceLocation UmbrellaLoc) {
   }
 
   // Look for this file.
-  const DirectoryEntry *Dir = 0;
+  const DirectoryEntry *Dir = nullptr;
   if (llvm::sys::path::is_absolute(DirName))
     Dir = SourceMgr.getFileManager().getDirectory(DirName);
   else {
@@ -2080,7 +2079,7 @@ void ModuleMapParser::parseInferredModuleDecl(bool Framework, bool Explicit) {
     case MMToken::ExcludeKeyword: {
       if (ActiveModule) {
         Diags.Report(Tok.getLocation(), diag::err_mmap_expected_inferred_member)
-          << (ActiveModule != 0);
+          << (ActiveModule != nullptr);
         consumeToken();
         break;
       }
@@ -2100,7 +2099,7 @@ void ModuleMapParser::parseInferredModuleDecl(bool Framework, bool Explicit) {
     case MMToken::ExportKeyword:
       if (!ActiveModule) {
         Diags.Report(Tok.getLocation(), diag::err_mmap_expected_inferred_member)
-          << (ActiveModule != 0);
+          << (ActiveModule != nullptr);
         consumeToken();
         break;
       }
@@ -2121,7 +2120,7 @@ void ModuleMapParser::parseInferredModuleDecl(bool Framework, bool Explicit) {
     case MMToken::UmbrellaKeyword:
     default:
       Diags.Report(Tok.getLocation(), diag::err_mmap_expected_inferred_member)
-          << (ActiveModule != 0);
+          << (ActiveModule != nullptr);
       consumeToken();
       break;        
     }
@@ -2257,7 +2256,7 @@ bool ModuleMap::parseModuleMapFile(const FileEntry *File, bool IsSystem) {
   if (Known != ParsedModuleMap.end())
     return Known->second;
 
-  assert(Target != 0 && "Missing target information");
+  assert(Target && "Missing target information");
   auto FileCharacter = IsSystem ? SrcMgr::C_System : SrcMgr::C_User;
   FileID ID = SourceMgr.createFileID(File, SourceLocation(), FileCharacter);
   const llvm::MemoryBuffer *Buffer = SourceMgr.getBuffer(ID);
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 537d5bf69da9..ba213a878ad2 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -45,7 +45,7 @@ MacroInfo *Preprocessor::AllocateMacroInfo() {
   }
 
   MIChain->Next = MIChainHead;
-  MIChain->Prev = 0;
+  MIChain->Prev = nullptr;
   if (MIChainHead)
     MIChainHead->Prev = MIChain;
   MIChainHead = MIChain;
@@ -111,7 +111,7 @@ void Preprocessor::ReleaseMacroInfo(MacroInfo *MI) {
   else {
     assert(MIChainHead == MIChain);
     MIChainHead = MIChain->Next;
-    MIChainHead->Prev = 0;
+    MIChainHead->Prev = nullptr;
   }
   MIChain->Next = MICache;
   MICache = MIChain;
@@ -154,7 +154,7 @@ void Preprocessor::ReadMacroName(Token &MacroNameTok, char isDefineUndef) {
   }
 
   IdentifierInfo *II = MacroNameTok.getIdentifierInfo();
-  if (II == 0) {
+  if (!II) {
     bool Invalid = false;
     std::string Spelling = getSpelling(MacroNameTok, &Invalid);
     if (Invalid)
@@ -418,7 +418,7 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
           // looked up, etc, inside the #elif expression.
           assert(CurPPLexer->LexingRawMode && "We have to be skipping here!");
           CurPPLexer->LexingRawMode = false;
-          IdentifierInfo *IfNDefMacro = 0;
+          IdentifierInfo *IfNDefMacro = nullptr;
           const bool CondValue = EvaluateDirectiveExpression(IfNDefMacro);
           CurPPLexer->LexingRawMode = true;
           if (Callbacks) {
@@ -515,7 +515,7 @@ void Preprocessor::PTHSkipExcludedConditionalBlock() {
       continue;
 
     // Evaluate the condition of the #elif.
-    IdentifierInfo *IfNDefMacro = 0;
+    IdentifierInfo *IfNDefMacro = nullptr;
     CurPTHLexer->ParsingPreprocessorDirective = true;
     bool ShouldEnter = EvaluateDirectiveExpression(IfNDefMacro);
     CurPTHLexer->ParsingPreprocessorDirective = false;
@@ -641,7 +641,7 @@ const FileEntry *Preprocessor::LookupFile(
   }
 
   // Otherwise, we really couldn't find the file.
-  return 0;
+  return nullptr;
 }
 
 
@@ -739,7 +739,7 @@ void Preprocessor::HandleDirective(Token &Result) {
     return HandleDigitDirective(Result);
   default:
     IdentifierInfo *II = Result.getIdentifierInfo();
-    if (II == 0) break;  // Not an identifier.
+    if (!II) break; // Not an identifier.
 
     // Ask what the preprocessor keyword ID is.
     switch (II->getPPKeywordID()) {
@@ -1204,7 +1204,7 @@ void Preprocessor::HandleMacroPublicDirective(Token &Tok) {
   MacroDirective *MD = getMacroDirective(II);
   
   // If the macro is not defined, this is an error.
-  if (MD == 0) {
+  if (!MD) {
     Diag(MacroNameTok, diag::err_pp_visibility_non_macro) << II;
     return;
   }
@@ -1231,7 +1231,7 @@ void Preprocessor::HandleMacroPrivateDirective(Token &Tok) {
   MacroDirective *MD = getMacroDirective(II);
   
   // If the macro is not defined, this is an error.
-  if (MD == 0) {
+  if (!MD) {
     Diag(MacroNameTok, diag::err_pp_visibility_non_macro) << II;
     return;
   }
@@ -1467,9 +1467,9 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
   }
   const FileEntry *File = LookupFile(
       FilenameLoc, LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename,
-      isAngled, LookupFrom, CurDir, Callbacks ? &SearchPath : NULL,
-      Callbacks ? &RelativePath : NULL,
-      HeaderInfo.getHeaderSearchOpts().ModuleMaps ? &SuggestedModule : 0);
+      isAngled, LookupFrom, CurDir, Callbacks ? &SearchPath : nullptr,
+      Callbacks ? &RelativePath : nullptr,
+      HeaderInfo.getHeaderSearchOpts().ModuleMaps ? &SuggestedModule : nullptr);
 
   if (Callbacks) {
     if (!File) {
@@ -1485,10 +1485,10 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
           File = LookupFile(FilenameLoc,
                             LangOpts.MSVCCompat ? NormalizedPath.c_str()
                                                 : Filename,
-                            isAngled, LookupFrom, CurDir, 0, 0,
+                            isAngled, LookupFrom, CurDir, nullptr, nullptr,
                             HeaderInfo.getHeaderSearchOpts().ModuleMaps
                                       ? &SuggestedModule
-                                      : 0,
+                                      : nullptr,
                             /*SkipCache*/ true);
         }
       }
@@ -1500,11 +1500,11 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
                                     LangOpts.MSVCCompat ? NormalizedPath.c_str()
                                                         : Filename,
                                     isAngled, FilenameRange, File, SearchPath,
-                                    RelativePath, /*ImportedModule=*/0);
+                                    RelativePath, /*ImportedModule=*/nullptr);
     }
   }
-  
-  if (File == 0) {
+
+  if (!File) {
     if (!SuppressIncludeNotFoundError) {
       // If the file could not be located and it was included via angle 
       // brackets, we can attempt a lookup as though it were a quoted path to
@@ -1512,9 +1512,10 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
       if (isAngled) {
         File = LookupFile(
             FilenameLoc, LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename,
-            false, LookupFrom, CurDir, Callbacks ? &SearchPath : 0,
-            Callbacks ? &RelativePath : 0,
-            HeaderInfo.getHeaderSearchOpts().ModuleMaps ? &SuggestedModule : 0);
+            false, LookupFrom, CurDir, Callbacks ? &SearchPath : nullptr,
+            Callbacks ? &RelativePath : nullptr,
+            HeaderInfo.getHeaderSearchOpts().ModuleMaps ? &SuggestedModule
+                                                        : nullptr);
         if (File) {
           SourceRange Range(FilenameTok.getLocation(), CharEnd);
           Diag(FilenameTok, diag::err_pp_file_not_found_not_fatal) << 
@@ -1595,7 +1596,7 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
     ModuleLoadResult Imported
       = TheModuleLoader.loadModule(IncludeTok.getLocation(), Path, Visibility,
                                    /*IsIncludeDirective=*/true);
-    assert((Imported == 0 || Imported == SuggestedModule.getModule()) &&
+    assert((Imported == nullptr || Imported == SuggestedModule.getModule()) &&
            "the imported module is different than the suggested one");
 
     if (!Imported && hadModuleLoaderFatalFailure()) {
@@ -1646,7 +1647,7 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
     Callbacks->InclusionDirective(HashLoc, IncludeTok, Filename, isAngled,
                                   FilenameRange, File,
                                   SearchPath, RelativePath,
-                                  /*ImportedModule=*/0);
+                                  /*ImportedModule=*/nullptr);
   }
   
   // The #included file will be considered to be a system header if either it is
@@ -1707,9 +1708,9 @@ void Preprocessor::HandleIncludeNextDirective(SourceLocation HashLoc,
   // diagnostic.
   const DirectoryLookup *Lookup = CurDirLookup;
   if (isInPrimaryFile()) {
-    Lookup = 0;
+    Lookup = nullptr;
     Diag(IncludeNextTok, diag::pp_include_next_in_primary);
-  } else if (Lookup == 0) {
+  } else if (!Lookup) {
     Diag(IncludeNextTok, diag::pp_include_next_absolute_path);
   } else {
     // Start looking up in the next directory.
@@ -1742,7 +1743,7 @@ void Preprocessor::HandleImportDirective(SourceLocation HashLoc,
       return HandleMicrosoftImportDirective(ImportTok);
     Diag(ImportTok, diag::ext_pp_import_directive);
   }
-  return HandleIncludeDirective(HashLoc, ImportTok, 0, true);
+  return HandleIncludeDirective(HashLoc, ImportTok, nullptr, true);
 }
 
 /// HandleIncludeMacrosDirective - The -imacros command line option turns into a
@@ -1763,7 +1764,7 @@ void Preprocessor::HandleIncludeMacrosDirective(SourceLocation HashLoc,
 
   // Treat this as a normal #include for checking purposes.  If this is
   // successful, it will push a new lexer onto the include stack.
-  HandleIncludeDirective(HashLoc, IncludeMacrosTok, 0, false);
+  HandleIncludeDirective(HashLoc, IncludeMacrosTok, nullptr, false);
 
   Token TmpTok;
   do {
@@ -1823,7 +1824,7 @@ bool Preprocessor::ReadMacroDefinitionArgList(MacroInfo *MI, Token &Tok) {
       // Handle keywords and identifiers here to accept things like
       // #define Foo(for) for.
       IdentifierInfo *II = Tok.getIdentifierInfo();
-      if (II == 0) {
+      if (!II) {
         // #define X(1
         Diag(Tok, diag::err_pp_invalid_tok_in_arg_list);
         return true;
@@ -2027,7 +2028,7 @@ void Preprocessor::HandleDefineDirective(Token &DefineTok,
       LexUnexpandedToken(Tok);
 
       // Check for a valid macro arg identifier.
-      if (Tok.getIdentifierInfo() == 0 ||
+      if (Tok.getIdentifierInfo() == nullptr ||
           MI->getArgumentNum(Tok.getIdentifierInfo()) == -1) {
 
         // If this is assembler-with-cpp mode, we accept random gibberish after
@@ -2143,7 +2144,7 @@ void Preprocessor::HandleUndefDirective(Token &UndefTok) {
 
   // Okay, we finally have a valid identifier to undef.
   MacroDirective *MD = getMacroDirective(MacroNameTok.getIdentifierInfo());
-  const MacroInfo *MI = MD ? MD->getMacroInfo() : 0;
+  const MacroInfo *MI = MD ? MD->getMacroInfo() : nullptr;
 
   // If the callbacks want to know, tell them about the macro #undef.
   // Note: no matter if the macro was defined or not.
@@ -2151,7 +2152,8 @@ void Preprocessor::HandleUndefDirective(Token &UndefTok) {
     Callbacks->MacroUndefined(MacroNameTok, MD);
 
   // If the macro is not defined, this is a noop undef, just return.
-  if (MI == 0) return;
+  if (!MI)
+    return;
 
   if (!MI->isUsed() && MI->isWarnIfUnused())
     Diag(MI->getDefinitionLoc(), diag::pp_macro_not_used);
@@ -2195,14 +2197,14 @@ void Preprocessor::HandleIfdefDirective(Token &Result, bool isIfndef,
 
   IdentifierInfo *MII = MacroNameTok.getIdentifierInfo();
   MacroDirective *MD = getMacroDirective(MII);
-  MacroInfo *MI = MD ? MD->getMacroInfo() : 0;
+  MacroInfo *MI = MD ? MD->getMacroInfo() : nullptr;
 
   if (CurPPLexer->getConditionalStackDepth() == 0) {
     // If the start of a top-level #ifdef and if the macro is not defined,
     // inform MIOpt that this might be the start of a proper include guard.
     // Otherwise it is some other form of unknown conditional which we can't
     // handle.
-    if (!ReadAnyTokensBeforeDirective && MI == 0) {
+    if (!ReadAnyTokensBeforeDirective && !MI) {
       assert(isIfndef && "#ifdef shouldn't reach here");
       CurPPLexer->MIOpt.EnterTopLevelIfndef(MII, MacroNameTok.getLocation());
     } else
@@ -2241,7 +2243,7 @@ void Preprocessor::HandleIfDirective(Token &IfToken,
   ++NumIf;
 
   // Parse and evaluate the conditional expression.
-  IdentifierInfo *IfNDefMacro = 0;
+  IdentifierInfo *IfNDefMacro = nullptr;
   const SourceLocation ConditionalBegin = CurPPLexer->getSourceLocation();
   const bool ConditionalTrue = EvaluateDirectiveExpression(IfNDefMacro);
   const SourceLocation ConditionalEnd = CurPPLexer->getSourceLocation();
diff --git a/clang/lib/Lex/PPExpressions.cpp b/clang/lib/Lex/PPExpressions.cpp
index 6975d31baba5..8be7a54f827c 100644
--- a/clang/lib/Lex/PPExpressions.cpp
+++ b/clang/lib/Lex/PPExpressions.cpp
@@ -104,7 +104,7 @@ static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
   }
   
   // If we don't have a pp-identifier now, this is an error.
-  if ((II = PeekTok.getIdentifierInfo()) == 0) {
+  if ((II = PeekTok.getIdentifierInfo()) == nullptr) {
     PP.Diag(PeekTok, diag::err_pp_defined_requires_identifier);
     return true;
   }
@@ -113,7 +113,7 @@ static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
   Result.Val = II->hasMacroDefinition();
   Result.Val.setIsUnsigned(false);  // Result is signed intmax_t.
 
-  MacroDirective *Macro = 0;
+  MacroDirective *Macro = nullptr;
   // If there is a macro, mark it used.
   if (Result.Val != 0 && ValueLive) {
     Macro = PP.getMacroDirective(II);
diff --git a/clang/lib/Lex/PPLexerChange.cpp b/clang/lib/Lex/PPLexerChange.cpp
index 0b1be09d8726..e79fbe192d6e 100644
--- a/clang/lib/Lex/PPLexerChange.cpp
+++ b/clang/lib/Lex/PPLexerChange.cpp
@@ -58,7 +58,7 @@ PreprocessorLexer *Preprocessor::getCurrentFileLexer() const {
     if (IsFileLexer(ISI))
       return ISI.ThePPLexer;
   }
-  return 0;
+  return nullptr;
 }
 
 
@@ -117,7 +117,7 @@ void Preprocessor::EnterSourceFileWithLexer(Lexer *TheLexer,
   CurLexer.reset(TheLexer);
   CurPPLexer = TheLexer;
   CurDirLookup = CurDir;
-  CurSubmodule = 0;
+  CurSubmodule = nullptr;
   if (CurLexerKind != CLK_LexAfterModuleImport)
     CurLexerKind = CLK_Lexer;
   
@@ -142,7 +142,7 @@ void Preprocessor::EnterSourceFileWithPTH(PTHLexer *PL,
   CurDirLookup = CurDir;
   CurPTHLexer.reset(PL);
   CurPPLexer = CurPTHLexer.get();
-  CurSubmodule = 0;
+  CurSubmodule = nullptr;
   if (CurLexerKind != CLK_LexAfterModuleImport)
     CurLexerKind = CLK_PTHLexer;
   
@@ -169,7 +169,7 @@ void Preprocessor::EnterMacro(Token &Tok, SourceLocation ILEnd,
   }
 
   PushIncludeMacroStack();
-  CurDirLookup = 0;
+  CurDirLookup = nullptr;
   CurTokenLexer.reset(TokLexer);
   if (CurLexerKind != CLK_LexAfterModuleImport)
     CurLexerKind = CLK_TokenLexer;
@@ -202,7 +202,7 @@ void Preprocessor::EnterTokenStream(const Token *Toks, unsigned NumToks,
 
   // Save our current state.
   PushIncludeMacroStack();
-  CurDirLookup = 0;
+  CurDirLookup = nullptr;
   CurTokenLexer.reset(TokLexer);
   if (CurLexerKind != CLK_LexAfterModuleImport)
     CurLexerKind = CLK_TokenLexer;
@@ -354,7 +354,7 @@ bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
         CurPTHLexer.reset();
       }
 
-      CurPPLexer = 0;
+      CurPPLexer = nullptr;
       return true;
     }
 
@@ -429,7 +429,7 @@ bool Preprocessor::HandleEndOfFile(Token &Result, bool isEndOfMacro) {
   }
   
   if (!isIncrementalProcessingEnabled())
-    CurPPLexer = 0;
+    CurPPLexer = nullptr;
 
   if (TUKind == TU_Complete) {
     // This is the end of the top-level file. 'WarnUnusedMacroLocs' has
@@ -561,11 +561,11 @@ void Preprocessor::HandleMicrosoftCommentPaste(Token &Tok) {
   // We handle this by scanning for the closest real lexer, switching it to
   // raw mode and preprocessor mode.  This will cause it to return \n as an
   // explicit EOD token.
-  PreprocessorLexer *FoundLexer = 0;
+  PreprocessorLexer *FoundLexer = nullptr;
   bool LexerWasInPPMode = false;
   for (unsigned i = 0, e = IncludeMacroStack.size(); i != e; ++i) {
     IncludeStackInfo &ISI = *(IncludeMacroStack.end()-i-1);
-    if (ISI.ThePPLexer == 0) continue;  // Scan for a real lexer.
+    if (ISI.ThePPLexer == nullptr) continue;  // Scan for a real lexer.
 
     // Once we find a real lexer, mark it as raw mode (disabling macro
     // expansions) and preprocessor mode (return EOD).  We know that the lexer
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index fa517e7fa811..4278faef7086 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -103,8 +103,8 @@ void Preprocessor::RegisterBuiltinMacros() {
     Ident__identifier = RegisterBuiltinMacro(*this, "__identifier");
     Ident__pragma = RegisterBuiltinMacro(*this, "__pragma");
   } else {
-    Ident__identifier = 0;
-    Ident__pragma = 0;
+    Ident__identifier = nullptr;
+    Ident__pragma = nullptr;
   }
 
   // Clang Extensions.
@@ -125,10 +125,10 @@ void Preprocessor::RegisterBuiltinMacros() {
     if (!LangOpts.CurrentModule.empty())
       Ident__MODULE__ = RegisterBuiltinMacro(*this, "__MODULE__");
     else
-      Ident__MODULE__ = 0;
+      Ident__MODULE__ = nullptr;
   } else {
-    Ident__building_module = 0;
-    Ident__MODULE__ = 0;
+    Ident__building_module = nullptr;
+    Ident__MODULE__ = nullptr;
   }
 }
 
@@ -140,7 +140,7 @@ static bool isTrivialSingleTokenExpansion(const MacroInfo *MI,
   IdentifierInfo *II = MI->getReplacementToken(0).getIdentifierInfo();
 
   // If the token isn't an identifier, it's always literally expanded.
-  if (II == 0) return true;
+  if (!II) return true;
 
   // If the information about this identifier is out of date, update it from
   // the external source.
@@ -228,7 +228,8 @@ bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier,
   // If this is a builtin macro, like __LINE__ or _Pragma, handle it specially.
   if (MI->isBuiltinMacro()) {
     if (Callbacks) Callbacks->MacroExpands(Identifier, MD,
-                                           Identifier.getLocation(),/*Args=*/0);
+                                           Identifier.getLocation(),
+                                           /*Args=*/nullptr);
     ExpandBuiltinMacro(Identifier);
     return true;
   }
@@ -236,7 +237,7 @@ bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier,
   /// Args - If this is a function-like macro expansion, this contains,
   /// for each macro argument, the list of tokens that were provided to the
   /// invocation.
-  MacroArgs *Args = 0;
+  MacroArgs *Args = nullptr;
 
   // Remember where the end of the expansion occurred.  For an object-like
   // macro, this is the identifier.  For a function-like macro, this is the ')'.
@@ -254,7 +255,7 @@ bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier,
     InMacroArgs = false;
 
     // If there was an error parsing the arguments, bail out.
-    if (Args == 0) return true;
+    if (!Args) return true;
 
     ++NumFnMacroExpanded;
   } else {
@@ -282,7 +283,8 @@ bool Preprocessor::HandleMacroExpandedIdentifier(Token &Identifier,
         for (unsigned i=0, e = DelayedMacroExpandsCallbacks.size(); i!=e; ++i) {
           MacroExpandsInfo &Info = DelayedMacroExpandsCallbacks[i];
           // FIXME: We lose macro args info with delayed callback.
-          Callbacks->MacroExpands(Info.Tok, Info.MD, Info.Range, /*Args=*/0);
+          Callbacks->MacroExpands(Info.Tok, Info.MD, Info.Range,
+                                  /*Args=*/nullptr);
         }
         DelayedMacroExpandsCallbacks.clear();
       }
@@ -557,7 +559,7 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
             << MacroName.getIdentifierInfo();
           // Do not lose the EOF/EOD.  Return it to the client.
           MacroName = Tok;
-          return 0;
+          return nullptr;
         } else {
           // Do not lose the EOF/EOD.
           Token *Toks = new Token[1];
@@ -589,7 +591,7 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
         // If this is a comment token in the argument list and we're just in
         // -C mode (not -CC mode), discard the comment.
         continue;
-      } else if (Tok.getIdentifierInfo() != 0) {
+      } else if (Tok.getIdentifierInfo() != nullptr) {
         // Reading macro arguments can cause macros that we are currently
         // expanding from to be popped off the expansion stack.  Doing so causes
         // them to be reenabled for expansion.  Here we record whether any
@@ -681,10 +683,10 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
           DB << *Range;
         }
       }
-      return 0;
+      return nullptr;
     }
     if (FixedNumArgs != MinArgsExpected)
-      return 0;
+      return nullptr;
 
     DiagnosticBuilder DB = Diag(MacroName, diag::note_suggest_parens_for_macro);
     for (SmallVector<SourceRange, 4>::iterator
@@ -751,7 +753,7 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
       Diag(Tok, diag::err_too_few_args_in_macro_invoc);
       Diag(MI->getDefinitionLoc(), diag::note_macro_here)
         << MacroName.getIdentifierInfo();
-      return 0;
+      return nullptr;
     }
 
     // Add a marker EOF token to the end of the token list for this argument.
@@ -773,7 +775,7 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
     Diag(MacroName, diag::err_too_many_args_in_macro_invoc);
     Diag(MI->getDefinitionLoc(), diag::note_macro_here)
       << MacroName.getIdentifierInfo();
-    return 0;
+    return nullptr;
   }
 
   return MacroArgs::create(MI, ArgTokens, isVarargsElided, *this);
@@ -788,7 +790,7 @@ Token *Preprocessor::cacheMacroExpandedTokens(TokenLexer *tokLexer,
                                               ArrayRef<Token> tokens) {
   assert(tokLexer);
   if (tokens.empty())
-    return 0;
+    return nullptr;
 
   size_t newIndex = MacroExpandedTokens.size();
   bool cacheNeedsToGrow = tokens.size() >
@@ -824,7 +826,7 @@ void Preprocessor::removeCachedMacroExpandedTokensOfLastLexer() {
 /// the identifier tokens inserted.
 static void ComputeDATE_TIME(SourceLocation &DATELoc, SourceLocation &TIMELoc,
                              Preprocessor &PP) {
-  time_t TT = time(0);
+  time_t TT = time(nullptr);
   struct tm *TM = localtime(&TT);
 
   static const char * const Months[] = {
@@ -1154,18 +1156,18 @@ static bool EvaluateHasIncludeCommon(Token &Tok,
   // Search include directories.
   const DirectoryLookup *CurDir;
   const FileEntry *File =
-      PP.LookupFile(FilenameLoc, Filename, isAngled, LookupFrom, CurDir, NULL,
-                    NULL, NULL);
+      PP.LookupFile(FilenameLoc, Filename, isAngled, LookupFrom, CurDir,
+                    nullptr, nullptr, nullptr);
 
   // Get the result value.  A result of true means the file exists.
-  return File != 0;
+  return File != nullptr;
 }
 
 /// EvaluateHasInclude - Process a '__has_include("path")' expression.
 /// Returns true if successful.
 static bool EvaluateHasInclude(Token &Tok, IdentifierInfo *II,
                                Preprocessor &PP) {
-  return EvaluateHasIncludeCommon(Tok, II, PP, NULL);
+  return EvaluateHasIncludeCommon(Tok, II, PP, nullptr);
 }
 
 /// EvaluateHasIncludeNext - Process '__has_include_next("path")' expression.
@@ -1177,9 +1179,9 @@ static bool EvaluateHasIncludeNext(Token &Tok,
   // issue a diagnostic.
   const DirectoryLookup *Lookup = PP.GetCurDirLookup();
   if (PP.isInPrimaryFile()) {
-    Lookup = 0;
+    Lookup = nullptr;
     PP.Diag(Tok, diag::pp_include_next_in_primary);
-  } else if (Lookup == 0) {
+  } else if (!Lookup) {
     PP.Diag(Tok, diag::pp_include_next_absolute_path);
   } else {
     // Start looking up in the next directory.
@@ -1252,7 +1254,7 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
   llvm::raw_svector_ostream OS(TmpBuffer);
 
   // Set up the return result.
-  Tok.setIdentifierInfo(0);
+  Tok.setIdentifierInfo(nullptr);
   Tok.clearFlag(Token::NeedsCleaning);
 
   if (II == Ident__LINE__) {
@@ -1341,7 +1343,7 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
 
     // Get the file that we are lexing out of.  If we're currently lexing from
     // a macro, dig into the include stack.
-    const FileEntry *CurFile = 0;
+    const FileEntry *CurFile = nullptr;
     PreprocessorLexer *TheLexer = getCurrentFileLexer();
 
     if (TheLexer)
@@ -1371,7 +1373,7 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
     SourceLocation StartLoc = Tok.getLocation();
 
     bool IsValid = false;
-    IdentifierInfo *FeatureII = 0;
+    IdentifierInfo *FeatureII = nullptr;
 
     // Read the '('.
     LexUnexpandedToken(Tok);
diff --git a/clang/lib/Lex/PTHLexer.cpp b/clang/lib/Lex/PTHLexer.cpp
index b888f2ed9b66..42629d41ab56 100644
--- a/clang/lib/Lex/PTHLexer.cpp
+++ b/clang/lib/Lex/PTHLexer.cpp
@@ -37,7 +37,7 @@ using namespace clang;
 
 PTHLexer::PTHLexer(Preprocessor &PP, FileID FID, const unsigned char *D,
                    const unsigned char *ppcond, PTHManager &PM)
-  : PreprocessorLexer(&PP, FID), TokBuf(D), CurPtr(D), LastHashTokPtr(0),
+  : PreprocessorLexer(&PP, FID), TokBuf(D), CurPtr(D), LastHashTokPtr(nullptr),
     PPCond(ppcond), CurPPCondPtr(ppcond), PTHMgr(PM) {
 
   FileStartLoc = PP.getSourceManager().getLocForStartOfFile(FID);
@@ -191,7 +191,7 @@ bool PTHLexer::SkipBlock() {
   assert(CurPPCondPtr && "No cached PP conditional information.");
   assert(LastHashTokPtr && "No known '#' token.");
 
-  const unsigned char* HashEntryI = 0;
+  const unsigned char *HashEntryI = nullptr;
   uint32_t TableIdx;
 
   do {
@@ -423,7 +423,7 @@ PTHManager::PTHManager(const llvm::MemoryBuffer* buf, void* fileLookup,
                        const char* originalSourceFile)
 : Buf(buf), PerIDCache(perIDCache), FileLookup(fileLookup),
   IdDataTable(idDataTable), StringIdLookup(stringIdLookup),
-  NumIds(numIds), PP(0), SpellingBase(spellingBase),
+  NumIds(numIds), PP(nullptr), SpellingBase(spellingBase),
   OriginalSourceFile(originalSourceFile) {}
 
 PTHManager::~PTHManager() {
@@ -445,7 +445,7 @@ PTHManager *PTHManager::Create(const std::string &file,
   if (llvm::MemoryBuffer::getFile(file, File)) {
     // FIXME: Add ec.message() to this diag.
     Diags.Report(diag::err_invalid_pth_file) << file;
-    return 0;
+    return nullptr;
   }
 
   using namespace llvm::support;
@@ -459,7 +459,7 @@ PTHManager *PTHManager::Create(const std::string &file,
   if ((BufEnd - BufBeg) < (signed)(sizeof("cfe-pth") + 4 + 4) ||
       memcmp(BufBeg, "cfe-pth", sizeof("cfe-pth")) != 0) {
     Diags.Report(diag::err_invalid_pth_file) << file;
-    return 0;
+    return nullptr;
   }
 
   // Read the PTH version.
@@ -471,7 +471,7 @@ PTHManager *PTHManager::Create(const std::string &file,
         Version < PTHManager::Version
         ? "PTH file uses an older PTH format that is no longer supported"
         : "PTH file uses a newer PTH format that cannot be read");
-    return 0;
+    return nullptr;
   }
 
   // Compute the address of the index table at the end of the PTH file.
@@ -479,7 +479,7 @@ PTHManager *PTHManager::Create(const std::string &file,
 
   if (PrologueOffset >= BufEnd) {
     Diags.Report(diag::err_invalid_pth_file) << file;
-    return 0;
+    return nullptr;
   }
 
   // Construct the file lookup table.  This will be used for mapping from
@@ -490,7 +490,7 @@ PTHManager *PTHManager::Create(const std::string &file,
 
   if (!(FileTable > BufBeg && FileTable < BufEnd)) {
     Diags.Report(diag::err_invalid_pth_file) << file;
-    return 0; // FIXME: Proper error diagnostic?
+    return nullptr; // FIXME: Proper error diagnostic?
   }
 
   std::unique_ptr<PTHFileLookup> FL(PTHFileLookup::Create(FileTable, BufBeg));
@@ -508,7 +508,7 @@ PTHManager *PTHManager::Create(const std::string &file,
 
   if (!(IData >= BufBeg && IData < BufEnd)) {
     Diags.Report(diag::err_invalid_pth_file) << file;
-    return 0;
+    return nullptr;
   }
 
   // Get the location of the hashtable mapping between strings and
@@ -518,7 +518,7 @@ PTHManager *PTHManager::Create(const std::string &file,
       BufBeg + endian::readNext<uint32_t, little, aligned>(StringIdTableOffset);
   if (!(StringIdTable >= BufBeg && StringIdTable < BufEnd)) {
     Diags.Report(diag::err_invalid_pth_file) << file;
-    return 0;
+    return nullptr;
   }
 
   std::unique_ptr<PTHStringIdLookup> SL(
@@ -530,7 +530,7 @@ PTHManager *PTHManager::Create(const std::string &file,
       BufBeg + endian::readNext<uint32_t, little, aligned>(spellingBaseOffset);
   if (!(spellingBase >= BufBeg && spellingBase < BufEnd)) {
     Diags.Report(diag::err_invalid_pth_file) << file;
-    return 0;
+    return nullptr;
   }
 
   // Get the number of IdentifierInfos and pre-allocate the identifier cache.
@@ -539,13 +539,13 @@ PTHManager *PTHManager::Create(const std::string &file,
   // Pre-allocate the persistent ID -> IdentifierInfo* cache.  We use calloc()
   // so that we in the best case only zero out memory once when the OS returns
   // us new pages.
-  IdentifierInfo** PerIDCache = 0;
+  IdentifierInfo **PerIDCache = nullptr;
 
   if (NumIds) {
     PerIDCache = (IdentifierInfo**)calloc(NumIds, sizeof(*PerIDCache));
     if (!PerIDCache) {
       InvalidPTH(Diags, "Could not allocate memory for processing PTH file");
-      return 0;
+      return nullptr;
     }
   }
 
@@ -553,7 +553,7 @@ PTHManager *PTHManager::Create(const std::string &file,
   const unsigned char* originalSourceBase = PrologueOffset + sizeof(uint32_t)*4;
   unsigned len =
       endian::readNext<uint16_t, little, unaligned>(originalSourceBase);
-  if (!len) originalSourceBase = 0;
+  if (!len) originalSourceBase = nullptr;
 
   // Create the new PTHManager.
   return new PTHManager(File.release(), FL.release(), IData, PerIDCache,
@@ -591,7 +591,7 @@ IdentifierInfo* PTHManager::get(StringRef Name) {
   PTHStringIdLookup::iterator I = SL.find(std::make_pair(Name.data(),
                                                          Name.size()));
   if (I == SL.end()) // No identifier found?
-    return 0;
+    return nullptr;
 
   // Match found.  Return the identifier!
   assert(*I > 0);
@@ -601,7 +601,7 @@ IdentifierInfo* PTHManager::get(StringRef Name) {
 PTHLexer *PTHManager::CreateLexer(FileID FID) {
   const FileEntry *FE = PP->getSourceManager().getFileEntryForID(FID);
   if (!FE)
-    return 0;
+    return nullptr;
 
   using namespace llvm::support;
 
@@ -612,7 +612,7 @@ PTHLexer *PTHManager::CreateLexer(FileID FID) {
   PTHFileLookup::iterator I = PFL.find(FE);
 
   if (I == PFL.end()) // No tokens available?
-    return 0;
+    return nullptr;
 
   const PTHFileData& FileData = *I;
 
@@ -623,7 +623,7 @@ PTHLexer *PTHManager::CreateLexer(FileID FID) {
   // Get the location of pp-conditional table.
   const unsigned char* ppcond = BufStart + FileData.getPPCondOffset();
   uint32_t Len = endian::readNext<uint32_t, little, aligned>(ppcond);
-  if (Len == 0) ppcond = 0;
+  if (Len == 0) ppcond = nullptr;
 
   assert(PP && "No preprocessor set yet!");
   return new PTHLexer(*PP, FID, data, ppcond, *this);
diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index 3e8a40312b44..b837fc5ef7c0 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -59,7 +59,7 @@ PragmaHandler *PragmaNamespace::FindHandler(StringRef Name,
                                             bool IgnoreNull) const {
   if (PragmaHandler *Handler = Handlers.lookup(Name))
     return Handler;
-  return IgnoreNull ? 0 : Handlers.lookup(StringRef());
+  return IgnoreNull ? nullptr : Handlers.lookup(StringRef());
 }
 
 void PragmaNamespace::AddPragma(PragmaHandler *Handler) {
@@ -88,7 +88,7 @@ void PragmaNamespace::HandlePragma(Preprocessor &PP,
     = FindHandler(Tok.getIdentifierInfo() ? Tok.getIdentifierInfo()->getName()
                                           : StringRef(),
                   /*IgnoreNull=*/false);
-  if (Handler == 0) {
+  if (!Handler) {
     PP.Diag(Tok, diag::warn_pragma_ignored);
     return;
   }
@@ -290,7 +290,7 @@ void Preprocessor::Handle_Pragma(Token &Tok) {
   Lexer *TL = Lexer::Create_PragmaLexer(TokLoc, PragmaLoc, RParenLoc,
                                         StrVal.size(), *this);
 
-  EnterSourceFileWithLexer(TL, 0);
+  EnterSourceFileWithLexer(TL, nullptr);
 
   // With everything set up, lex this as a #pragma directive.
   HandlePragmaDirective(PragmaLoc, PIK__Pragma);
@@ -473,8 +473,9 @@ void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
   // Search include directories for this file.
   const DirectoryLookup *CurDir;
   const FileEntry *File = LookupFile(FilenameTok.getLocation(), Filename,
-                                     isAngled, 0, CurDir, NULL, NULL, NULL);
-  if (File == 0) {
+                                     isAngled, nullptr, CurDir, nullptr,
+                                     nullptr, nullptr);
+  if (!File) {
     if (!SuppressIncludeNotFoundError)
       Diag(FilenameTok, diag::err_pp_file_not_found) << Filename;
     return;
@@ -510,7 +511,7 @@ IdentifierInfo *Preprocessor::ParsePragmaPushOrPopMacro(Token &Tok) {
   if (Tok.isNot(tok::l_paren)) {
     Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
       << getSpelling(PragmaTok);
-    return 0;
+    return nullptr;
   }
 
   // Read the macro name string.
@@ -518,12 +519,12 @@ IdentifierInfo *Preprocessor::ParsePragmaPushOrPopMacro(Token &Tok) {
   if (Tok.isNot(tok::string_literal)) {
     Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
       << getSpelling(PragmaTok);
-    return 0;
+    return nullptr;
   }
 
   if (Tok.hasUDSuffix()) {
     Diag(Tok, diag::err_invalid_string_udl);
-    return 0;
+    return nullptr;
   }
 
   // Remember the macro string.
@@ -534,7 +535,7 @@ IdentifierInfo *Preprocessor::ParsePragmaPushOrPopMacro(Token &Tok) {
   if (Tok.isNot(tok::r_paren)) {
     Diag(PragmaTok.getLocation(), diag::err_pragma_push_pop_macro_malformed)
       << getSpelling(PragmaTok);
-    return 0;
+    return nullptr;
   }
 
   assert(StrVal[0] == '"' && StrVal[StrVal.size()-1] == '"' &&
@@ -736,7 +737,7 @@ void Preprocessor::AddPragmaHandler(StringRef Namespace,
     // we already have the namespace to insert into.
     if (PragmaHandler *Existing = PragmaHandlers->FindHandler(Namespace)) {
       InsertNS = Existing->getIfNamespace();
-      assert(InsertNS != 0 && "Cannot have a pragma namespace and pragma"
+      assert(InsertNS != nullptr && "Cannot have a pragma namespace and pragma"
              " handler with the same name!");
     } else {
       // Otherwise, this namespace doesn't exist yet, create and insert the
diff --git a/clang/lib/Lex/PreprocessingRecord.cpp b/clang/lib/Lex/PreprocessingRecord.cpp
index db5a9f93cf03..41bb581bb0aa 100644
--- a/clang/lib/Lex/PreprocessingRecord.cpp
+++ b/clang/lib/Lex/PreprocessingRecord.cpp
@@ -40,7 +40,7 @@ InclusionDirective::InclusionDirective(PreprocessingRecord &PPRec,
 
 PreprocessingRecord::PreprocessingRecord(SourceManager &SM)
   : SourceMgr(SM),
-    ExternalSource(0) {
+    ExternalSource(nullptr) {
 }
 
 /// \brief Returns a pair of [Begin, End) iterators of preprocessed entities
@@ -334,7 +334,7 @@ PreprocessedEntity *PreprocessingRecord::getPreprocessedEntity(PPEntityID PPID){
   }
 
   if (PPID.ID == 0)
-    return 0;
+    return nullptr;
   unsigned Index = PPID.ID - 1;
   assert(Index < PreprocessedEntities.size() &&
          "Out-of bounds local preprocessed entity");
@@ -361,7 +361,7 @@ MacroDefinition *PreprocessingRecord::findMacroDefinition(const MacroInfo *MI) {
   llvm::DenseMap<const MacroInfo *, MacroDefinition *>::iterator Pos
     = MacroDefinitions.find(MI);
   if (Pos == MacroDefinitions.end())
-    return 0;
+    return nullptr;
 
   return Pos->second;
 }
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index 5072978ed65c..b561636a1627 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -62,14 +62,15 @@ Preprocessor::Preprocessor(IntrusiveRefCntPtr<PreprocessorOptions> PPOpts,
                            TranslationUnitKind TUKind)
     : PPOpts(PPOpts), Diags(&diags), LangOpts(opts), Target(0),
       FileMgr(Headers.getFileMgr()), SourceMgr(SM), HeaderInfo(Headers),
-      TheModuleLoader(TheModuleLoader), ExternalSource(0),
+      TheModuleLoader(TheModuleLoader), ExternalSource(nullptr),
       Identifiers(opts, IILookup), IncrementalProcessing(false), TUKind(TUKind),
-      CodeComplete(0), CodeCompletionFile(0), CodeCompletionOffset(0),
-      LastTokenWasAt(false), ModuleImportExpectsIdentifier(false),
-      CodeCompletionReached(0), SkipMainFilePreamble(0, true), CurPPLexer(0),
-      CurDirLookup(0), CurLexerKind(CLK_Lexer), CurSubmodule(0), Callbacks(0),
-      MacroArgCache(0), Record(0), MIChainHead(0), MICache(0),
-      DeserialMIChainHead(0) {
+      CodeComplete(nullptr), CodeCompletionFile(nullptr),
+      CodeCompletionOffset(0), LastTokenWasAt(false),
+      ModuleImportExpectsIdentifier(false), CodeCompletionReached(0),
+      SkipMainFilePreamble(0, true), CurPPLexer(nullptr),
+      CurDirLookup(nullptr), CurLexerKind(CLK_Lexer), CurSubmodule(nullptr),
+      Callbacks(nullptr), MacroArgCache(nullptr), Record(nullptr),
+      MIChainHead(nullptr), MICache(nullptr), DeserialMIChainHead(0) {
   OwnsHeaderSearch = OwnsHeaders;
   
   ScratchBuf = new ScratchBuffer(SourceMgr);
@@ -127,9 +128,11 @@ Preprocessor::Preprocessor(IntrusiveRefCntPtr<PreprocessorOptions> PPOpts,
     Ident___abnormal_termination = getIdentifierInfo("__abnormal_termination");
     Ident_AbnormalTermination    = getIdentifierInfo("AbnormalTermination");
   } else {
-    Ident__exception_info = Ident__exception_code = Ident__abnormal_termination = 0;
-    Ident___exception_info = Ident___exception_code = Ident___abnormal_termination = 0;
-    Ident_GetExceptionInfo = Ident_GetExceptionCode = Ident_AbnormalTermination = 0;
+    Ident__exception_info = Ident__exception_code = nullptr;
+    Ident__abnormal_termination = Ident___exception_info = nullptr;
+    Ident___exception_code = Ident___abnormal_termination = nullptr;
+    Ident_GetExceptionInfo = Ident_GetExceptionCode = nullptr;
+    Ident_AbnormalTermination = nullptr;
   }
 }
 
@@ -438,8 +441,8 @@ void Preprocessor::CreateString(StringRef Str, Token &Tok,
 
 Module *Preprocessor::getCurrentModule() {
   if (getLangOpts().CurrentModule.empty())
-    return 0;
-  
+    return nullptr;
+
   return getHeaderSearchInfo().lookupModule(getLangOpts().CurrentModule);
 }
 
@@ -461,8 +464,8 @@ void Preprocessor::EnterMainSourceFile() {
   // a main file.
   if (!SourceMgr.isLoadedFileID(MainFileID)) {
     // Enter the main file source buffer.
-    EnterSourceFile(MainFileID, 0, SourceLocation());
-  
+    EnterSourceFile(MainFileID, nullptr, SourceLocation());
+
     // If we've been asked to skip bytes in the main file (e.g., as part of a
     // precompiled preamble), do so now.
     if (SkipMainFilePreamble.first > 0)
@@ -484,7 +487,7 @@ void Preprocessor::EnterMainSourceFile() {
   setPredefinesFileID(FID);
 
   // Start parsing the predefines.
-  EnterSourceFile(FID, 0, SourceLocation());
+  EnterSourceFile(FID, nullptr, SourceLocation());
 }
 
 void Preprocessor::EndSourceFile() {
@@ -630,7 +633,7 @@ bool Preprocessor::HandleIdentifier(Token &Identifier) {
   // then we act as if it is the actual operator and not the textual
   // representation of it.
   if (II.isCPlusPlusOperatorKeyword())
-    Identifier.setIdentifierInfo(0);
+    Identifier.setIdentifierInfo(nullptr);
 
   // If this is an extension token, diagnose its use.
   // We avoid diagnosing tokens that originate from macro definitions.
diff --git a/clang/lib/Lex/ScratchBuffer.cpp b/clang/lib/Lex/ScratchBuffer.cpp
index 984a0c154afe..d7104b178860 100644
--- a/clang/lib/Lex/ScratchBuffer.cpp
+++ b/clang/lib/Lex/ScratchBuffer.cpp
@@ -21,7 +21,8 @@ using namespace clang;
 //than a page, almost certainly enough for anything. :)
 static const unsigned ScratchBufSize = 4060;
 
-ScratchBuffer::ScratchBuffer(SourceManager &SM) : SourceMgr(SM), CurBuffer(0) {
+ScratchBuffer::ScratchBuffer(SourceManager &SM)
+    : SourceMgr(SM), CurBuffer(nullptr) {
   // Set BytesUsed so that the first call to getToken will require an alloc.
   BytesUsed = ScratchBufSize;
 }
diff --git a/clang/lib/Lex/TokenLexer.cpp b/clang/lib/Lex/TokenLexer.cpp
index 3cb0648a0102..9d03e8d30b8b 100644
--- a/clang/lib/Lex/TokenLexer.cpp
+++ b/clang/lib/Lex/TokenLexer.cpp
@@ -86,8 +86,8 @@ void TokenLexer::Init(const Token *TokArray, unsigned NumToks,
   // associated with it.
   destroy();
 
-  Macro = 0;
-  ActualArgs = 0;
+  Macro = nullptr;
+  ActualArgs = nullptr;
   Tokens = TokArray;
   OwnsTokens = ownsTokens;
   DisableMacroExpansion = disableMacroExpansion;
@@ -113,7 +113,7 @@ void TokenLexer::destroy() {
   // the expanded tokens.
   if (OwnsTokens) {
     delete [] Tokens;
-    Tokens = 0;
+    Tokens = nullptr;
     OwnsTokens = false;
   }
 
@@ -480,7 +480,7 @@ bool TokenLexer::Lex(Token &Tok) {
   HasLeadingSpace = false;
 
   // Handle recursive expansion!
-  if (!Tok.isAnnotation() && Tok.getIdentifierInfo() != 0) {
+  if (!Tok.isAnnotation() && Tok.getIdentifierInfo() != nullptr) {
     // Change the kind of this identifier to the appropriate token kind, e.g.
     // turning "for" into a keyword.
     IdentifierInfo *II = Tok.getIdentifierInfo();
@@ -507,7 +507,7 @@ bool TokenLexer::Lex(Token &Tok) {
 /// If this returns true, the caller should immediately return the token.
 bool TokenLexer::PasteTokens(Token &Tok) {
   SmallString<128> Buffer;
-  const char *ResultTokStrPtr = 0;
+  const char *ResultTokStrPtr = nullptr;
   SourceLocation StartLoc = Tok.getLocation();
   SourceLocation PasteOpLoc;
   do {